Search Publications
Tracking the Evolution of a Coherent Magnetic Flux Rope Continuously from the Inner to the Outer Corona
Cheng, X.; Ding, M. D.; Zhang, J. +6 more
The magnetic flux rope (MFR) is believed to be the underlying magnetic structure of coronal mass ejections (CMEs). However, it remains unclear how an MFR evolves into and forms the multi-component structure of a CME. In this paper, we perform a comprehensive study of an extreme-ultraviolet (EUV) MFR eruption on 2013 May 22 by tracking its morpholo…
The Variable Hard X-Ray Emission of NGC 4945 as Observed by NuSTAR
Hailey, Charles J.; Brandt, William N.; Comastri, Andrea +19 more
We present a broadband (~0.5-79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC 4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (>10 keV) flux and spectral variability, with flux variations of a factor of two on timescales of 20 ks. A variable p…
Primordial power spectrum from Planck
Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun
Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra from Planck to reconstruct the shape of the primordial power spectrum and locate possible features. Performing …
The rarity of dust in metal-poor galaxies
Sandstrom, Karin M.; Bolatto, Alberto D.; Leroy, Adam K. +7 more
Galaxies observed at redshift z>6, when the Universe was less than a billion years old, thus far very rarely show evidence of the cold dust that accompanies star formation in the local Universe, where the dust-to-gas mass ratio is around one per cent. A prototypical example is the galaxy Himiko (z = 6.6), which--a mere 840million years after th…
Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies
Peloso, Marco; Contaldi, Carlo R.; Sorbo, Lorenzo
The BICEP2 collaboration has reported a strong B mode signal in the CMB polarization, which is well fit by a tensor-to-scalar ratio of r simeq 0.2. This is greater than the upper limit r < 0.11 obtained from the temperature anisotropies under the assumption of a constant scalar spectral index ns. This discrepancy can be reduced once …
Coupling of oxygen, nitrogen, and hydrocarbon species in the photochemistry of Titan's atmosphere
Dobrijevic, M.; Loison, J. C.; Hickson, K. M. +1 more
Analysis of recent detections of water by Herschel/HIFI-PACS and Cassini/CIRS suggest for a steep gradient of the water profile in the lower stratosphere of Titan's atmosphere (Cottini, V., Nixon, C.A., Jennings, D.E., Anderson, C.M., Gorius, N., Bjoraker, G.L., Coustenis, A., Teanby, N.A., Achterberg, R.K., Béezard, B., de Kok, R., Lellouch, E., …
A Reconnaissance of the Possible Donor Stars to the Kepler Supernova
Schmidt, Brian P.; Do, Tuan; Scharwächter, Julia +2 more
The identity of Type Ia supernova progenitors remains a mystery, with various lines of evidence pointing toward either accretion from a nondegenerate companion or the rapid merger of two degenerate stars leading to the thermonuclear destruction of a white dwarf. In this paper, we spectroscopically scrutinize 24 of the brightest stars residing in t…
Faint Submillimeter Galaxies Revealed by Multifield Deep ALMA Observations: Number Counts, Spatial Clustering, and a Dark Submillimeter Line Emitter
Ono, Yoshiaki; Ouchi, Masami; Kurono, Yasutaka +1 more
We present the statistics of faint submillimeter/millimeter galaxies (SMGs) and serendipitous detections of a submillimeter/millimeter line emitter (SLE) with no multi-wavelength continuum counterpart revealed by the deep ALMA observations. We identify faint SMGs with flux densities of 0.1-1.0 mJy in the deep Band-6 and Band-7 maps of 10 independe…
Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds
Kneissl, R.; Miville-Deschênes, M. -A.; Boulanger, F. +183 more
Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small spinning dust grains. The aim of this paper is a statistical study of the basic properties of AME regions and the environment in which they emit. We used WMAP and Planck maps, combined with ancillary radio and IR data, to construct a sample of 98 candi…
Magnetohydrodynamic Simulation of the X2.2 Solar Flare on 2011 February 15. I. Comparison with the Observations
Choe, G. S.; Park, Y. D.; Inoue, S. +2 more
We performed a magnetohydrodynamic (MHD) simulation using a nonlinear force-free field (NLFFF) in solar active region 11158 to clarify the dynamics of an X2.2-class solar flare. We found that the NLFFF never shows the dramatic dynamics seen in observations, i.e., it is in a stable state against the perturbations. On the other hand, the MHD simulat…